The present invention relates to a process for the processing of digitized signals representing an original image and in particular an image defined by scanning lines, such as e.g. an image produced from video signals. This invention applies to the restoration and improvement of contrasts in video-type images, to the detection of the contours and the structuring of the images.
It is known to process digitized images representing an original image, defined by scanning lines, using a module making it possible to process each image element or picture element (called "pixel") using a mathematical or so-called convolution method. Each image element or pixel a.sub.ij of the original image to be processed is defined by its intensity a in the form of E bits and its coordinates i and j, i being the number of a considered scanning line of said original image and j the number of the picture element on said scanning line. The original image is processed by convolution, by a convolution window of dimensions L.times.P comprising L lines of P coefficients. Each of these weighting factors or coefficients C.sub.1,k is defined by its value C and its coordinates l and k within the window. Each window is centred on the corresponding image element a.sub.ij. The processing module supplies for each image element a.sub.i,j of the original image, an image element b.sub.i,j of a convoluted image, defined by its intensity b, in the form of G bits and its coordinates i and j. The image element b.sub.ij is obtained from successive sums of products defined by the relation: ##EQU1##
In this relation 1 varies from l to L and k varies from l to P. Obviously, i, j, l, k, L, P, E, G are integers.
A known convolution processing module is e.g. described in the journal Computer Vision, Graphics and Image Processing, vol. 27, pp. 115 to 123, 1984. A module of this type is also described in IEEE article entitled "Large Array VLSI Filter", vol. 83-CH 1929-9, 1983, pp. 15 to 21.
The processes for the processing of digitized signals representing an original image using this type of modulus only make it possible to process images in which each line comprises a predetermined number N of image elements, each image element being represented by a fixed number E of bits and in which the convolution processing window has fixed dimensions L.times.P and non-programmable coefficients. Thus, with a given convolution processing module it is not possible to process images in which the number of picture elements per line differs from that for which the module is designed, or to process images in which each picture element is represented by a number of bits differing from that of the picture elements for which the module is designed. It is also very difficult when using such a module to process images in which the convolution window does not have the dimensions L.times.P for which the module was designed. Generally, the processing of the image elements of an image, whose characteristics do not correspond to those of the picture elements of the image to be processed is impossible, even when using complicated circuits associated with said module. Thus, for an image having predetermined characteristics (number of picture elements per line, number of bits defining each picture element, convolution window dimensions), it is necessary to construct a specific model, bearing in mind the characteristics of said original image to be processed in order to obtain a convoluted image. This also applies in the case of an application chain and when it is necessary to modify the coefficients of the convolution window.